The Left Hand Rules


From jmoney114 and physick.wikispaces.com
The First Left Hand Rule!
Heres the deal:
"point the thumb of your left hand in the direction of the current flow! Let your fingers curl around the wire! The direction of your fingers is the direction of the magnetic field"

What if your more of a picture person.. well dont worry I have one of those too!
Firstlhr.jpg

As you can see from the photo above, the thumb is pointed in the direction of the electrical current (I) and the fingers are curling around the wire representing the magnetic field (B)

When you see a symbol such as this: When you see a symbol such as this:
current out of page.jpg current going into page.jpg
The current is going OUT OF THE PAGE! The current is going INTO THE PAGE!

The Second Left Hand Rule!
The second left hand rule is not necessarily anymore difficult than the first it just obtains to different things,
The reason why the second left hand rule is different is because it involves a solenoid.

A solenoid is a electromagnet
  • The wires produce a magnetic field hense the name electromagnet
  • the b-field is uniform nad straight inside the solenoid
  • outside the solenoid, the field is compartively weak and is the same shape as a field around a bar magnet

Heres a solenoid!
Picture_of_solenoid.png
Heres the deal with the second left hand rule:
"To determine the direcrtion of the current b-field in a solenoid curl your fingers and point your thumb. Your fingers move in the direction of the current flow and the thumb moves in the direction of the B-Field. The thumb also points to North (N) on the solenoid."
And Again for the picture people

right_hand_grip_rule_2.jpg

The Third Left Hand rule!
the third left hand rule plays a role in helping to distinguish the magnetic force

the Fs acts perpendicularily to the current and the B- Field

Heres the deal:
your thumb = the direction of the current
your index finger = external b-field
middle = Fs

Heres a picture example of the third left hand rule!
left-hand-rule.jpg

Third Left Hand RuleLeft Hand Rule #1









References

  1. All sources of information were obtained from notebook, and notes taken within class
  2. http://www.google.ca/imgresq=third+left+hand+rule&um=1rule